Jeb Bush is endorsing Mitt Romney for president, he announced on Wednesday.

In a statement, the former Florida governor congratulated Romney for his primary win in Illinois Tuesday night -- and called on his fellow Republicans to unite behind the former Massachusetts governor as the party's presidential nominee.

"Congratulations to Governor Mitt Romney on his win last night and to all the candidates for a hard fought, thoughtful debate and primary season," Bush said in the statement. "Primary elections have been held in thirty-four states, and now is the time for Republicans to unite behind Governor Romney and take our message of fiscal conservatism and job creation to all voters this fall."

He continued: "I am endorsing Mitt Romney for our Party's nomination. We face huge challenges, and we need a leader who understands the economy, recognizes more government regulation is not the answer, believes in entrepreneurial capitalism and works to ensure that all Americans have the opportunity to succeed."

Bush, who is the brother and son of former presidents George W. Bush and George H.W. Bush respectively, had up to this point declined to endorse a candidate, including during the Florida primary, when he told Bloomberg he would "stay neutral."

"He has been watching the race and made the decision to endorse this morning. He called Gov. Romney this morning," a Bush spokesperson told CBS News on Wednesday. The spokesperson said Bush has no plans at this time to make a public appearance with Romney.

In a statement, the Romney campaign expressed "tremendous pride" at the endorsement, and praised Bush's "outstanding ability to bring people together."

"Jeb Bush is synonymous with good government and with conservative policies that yield results," the statement said. "He has long demonstrated an outstanding ability to bring people together. I therefore take tremendous pride in having earned his endorsement. This is a key moment in the presidential contest and Jeb's counsel and support will be critical in the coming months in my effort to defeat Barack Obama and turn around our country."

Last month, Bush said he found the rhetoric being touted in the Republican presidential debates"a little troubling"because the candidates were appealing to voters' "fears and emotion" rather than more overarching political concerns.

"I used to be a conservative and I watch these debates and I'm wondering, I don't think I've changed, but it's a little troubling sometimes when people are appealing to people's fears and emotion rather than trying to get them to look over the horizon for a broader perspective and that's kind of where we are," Bush said after a February speech in Dallas.

The former governor, who has led efforts to forge a stronger relationship between the Latino and Republican communities, has also warned the GOP presidential candidates against alienating Hispanic voters ahead of the general election.

"That could be an issue in the general election that plays out in a negative way for Republican candidates," Bush told Bloomberg in January. "In swing-states, Hispanic voters are increasingly the swing voters, and if you, by your tone more than anything else, send a signal that 'you're not wanted on my team' -- and I'm not saying any candidate has done that -- you could alienate voters that could be part of the winning" equation toward winning the presidency.

In the same interview, Bush said "I don't agree with Mitt's views on immigration in their totality but that's OK."

"My not endorsing him does not relate to any particular issue," he said at the time.

Bush has supported immigration reform, and has gone so far as to say he is "supportive" of the goals outlined in the DREAM Act, an immigration measure that would give upstanding undocumented immigrants who were brought to America as children a pathway to citizenship.

"The answer is self-deportation, which is people decide they can do better by going home because they can't find work here because they don't have legal documentation to allow them to work here," he saidin a January debate. "And so we're not going to round people up."

Following Romney's clear-cut victory in the Illinois primaryTuesday night, there is likely to be increased pressure on the candidate's rivals to drop out of the race, theoretically allowing the party to coalesce behind a single candidate.

"It goes without saying, but if Romney is going to close the door on this contest he's going to need help from people like Jeb Bush, Haley Barbour and Mitch Daniels," said CBS News political director John Dickerson. "There aren't many wise men left in either party but those three are the closest thing we have to modern day wise men who can weigh in and generate a few news cycles of coverage."

"Bush's endorsement is not exactly a ringing endorsement of the man Mitt Romney--'it's time to close ranks' is less powerful than 'we love Mitt'-- but it comes at just the right time," Dickerson added.

In remarks to reporters after Bush's announcement, Gingrich spokesman R.C. Hammond suggested the campaign was not impressed by the endorsement.

"It's the completion of the establishment trifecta," Hammond said, referring to to Bob Dole, former president George H.W. Bush and Jeb Bush, all of whom have now endorsed Romney.

When asked by reporters Wednesday if he agrees that it's time for the Republican party to come together to support a candidate, Rick Santorum said, "I agree -- they should all start supporting me."